Grinding machine



Dec, 19, 1950 w. H. WOOD GRINDING MACHINE 8 Sheets-Sheet 1 Filed Nov. 28, 1947 Inventor b/aLLace H Mood By M LEA Ian.

fitter-nay Dec. 19,, 1950 w. H. WOOD 2,534,937

GRINDING MACHINE 8 Sheets-Sheet 3 Fij. 3

Filed Nov. 28, 1947 Inventor A/aLLace, H. L/ooat Fig/5 I y W mat.

Httorney Dec. 19, 1950 w. H. WOOD 2,534,937

GRINDING MACHINE Filed Nov. 28, 1947 8 Sheets-Sheet 4 /NVENTOI8 WALLACE H. W000 HTromvcy Fi].6 By aim-E I Dec. 19, 1950 w. H. WOOD v 2,534,937

GRINDING MACHINE Filed Nov. 28, 1947 8 Sheets-Sheet 5 /N v: N roe WALLACE H. W000 Mush I) rroenay Dec. 19,1950 w. H. WOOD 2,534,937 GRINDING MACHINE Filed Nov. 28, 1947 .8 Sheets-Sheet 6 [a5 Fi I1 WALLACE H. W000 a]. 10 r mu we z rromlay lNVENTOR.

Dec. 19, 1950 w. H. WOOD GRINDING MACHINE 8 Sheets-Sheet 7 Filed Nov. 28, 1947 Invcntor lL/alLace H. wood.

, y MU -W Dec. 19, 1950 w. H. WOOD 2,534,937

GRINDING MACHINE Filed Nov. 28, 1947 a heets-Sheet s I'm/onto? LL/aLLLzLce H. Mood/ Httorvey Patented Dec. 19, 1950 GRINDING MACHINE Wallace H. Wood, Worcester, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application November 28, 1947, Serial No. 788,725

13 Claims. 1

The invention relates to a. grinding machine and more particularly to a hydraulically operated grinding machine.

One object of the invention is to provide a simple and thoroughly practical hydraulically operated grinding machine. Another object is to provide an improved hydraulic table reciprocating mechanism.

Another object is to provide a table-actuated pilot valve and a reversing valve which are simultaneously shifted by table movement until exhaust of fluid is cut off from table cylinder to stop the table, after which the pilot valve directs fluid under pressure through a throttle valve into an end chamber in the reversing valve to shift the reversing valve at a slow rate (dwell) and a by-pass port opened thereafter to admit fluid under pressure rapidly to snap the reverse valve into a reverse position.

Another object of the invention is to provide means actuated by the feed control valve automatically to bleed the pressure end of the table cylinder thereby eliminating air which may leak into the system.

Another object is to provide a hydraulic vanetype motor to feed the grinding wheel and a control valve therefor which is actuated by and in timed relation with the table reverse valve so as to produce an infeed during table reversal. Another object is to provide a slidable sleeve for the feed control valve which automatically resets the timing of the valve ahead of the dead center for the reverse stroke so that an infeed of the grinding wheel is completed before the table starts its traverse in the opposite direction.

Another object is to provide a direct by-pass to pass fluid under pressure directly from the pump (pressure line) to the reservoir when the machine is idle thereby eliminating wire-drawing of the fluid and the resultant heating of the fluid.

A further object is to provide a start and stop valve which is arranged when shifted to a start position to actuate a cam mechanim to disengage clutch to render hand traverse mechanism inoperative and to open a V-port so as to start reciprocation of the table.

A further object is to provide a start and stop valve which is arranged when shifted to a stop position (1) to close a V-port to stop table reciprocation, (2) cam recedes to render hand traverse mechanism operative, (3) opens by-pass between opposite ends of table cylinder to facilitate manual operation of table, and (4) open bypass to pass fluid under pressure directly from the pump to the reservoir.

Other objects will be in part obvious or in part pointed out hereinafter.

This invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplifled in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is fragmentary front elevation of the improved grinding machine;

Fig. 2 is a fragmentary'cross sectional view through the grinding machine, taken apprOxL- mately on the line 2-2 of Fig. 1, showing the wheel feeding mechanism;

Fig. 3 is a vertical sectional view, on an enlarged scale, taken approximately on the line 33 of Fig. 1, through the hydraulic wheel feed motor;

Fig. 4 is a vertical sectional view, taken approximately on the line 4-4, through the hydraulic feed motor;

Fig. 5 is a fragmentary vertical sectional view, taken approximately on the line 5-5 of Fig. 3;

Fig. 6 is a vertical sectional view, on an enlarged scale, taken approximately on the line 6--6 of Fig. 1, through the actuating mechanism for the table pilot and reversing valves;

Fig. 7 is a fragmentary front elevation of the actuating mechanism for the table pilot and reversing valves;

Fig. 8 is a vertical sectional view, on an enlarged scale, taken approximately on the line 88 of .Fig. 1, through the start-stop and speed control lever and valve;

Fig. 9 is a horizontal sectional view, on an enlarged scale, taken approximately on the line 9-9 of Fig. 8, through the pilot and reversing valves;

Fig. 10 is a fragment ry plan view. on an enlarged scale, of the hydraulic table cylinder and the control valve unit therefor;

Fig. 11 is a vertical sectional view, taken approximately on the line llll of Fig. 10, showing the table cylinder and control valve unit in elevation;

Fig. 12 is a fragmentary plan view, on an enlarged scale, of the manually operable table traverse mechanism;

Fig. 13 is a horizontal sectional view, on an enlarged scale, taken approximately on the line l3-l3 of Fig. 1, through the manually operble table traverse mechanism;

Fig. 14 is a diagrammatic illustration of the hydraulic control mechanism and the piping therefor; I

Fig. is a fragmentary vertical sectional view, on an enlarged scale, through the wheel feed motor control valve;

Fig. 16 is a horizontal sectional view, taken approximately on the line IBI6 of Fig. 15, through the wheel feed motor control valve; and

Fig. 17 is a plan view of the table reversing valve sleeve, on an enlarged scale, showing the orts. D An improved hydraulically operated grinding machine has been illustrated in the drawings comprising a base 10 which serves as a support for a longitudinally reciprocable work supporting table I l. The table I l is arranged to be traversed or reciprocated longitudinally on a flat way I! and a V-way l3 formed on the upper surface of the base Ill.

The table I I serves as a support for a headstock I4 having a headstock center i5 and a footstock l6 having a footstock center II rotatably to support opposite ends of a work piece to be ground. An electric motor i8 is mounted on the headstock l4 to drive the work.

The base I8 also serves as a support for a transversely movable wheel slide 2i which is arranged to slide transversely on the usual ways (not shown) on a wheel slide base 22. The wheel slide 2| is providedon its upper surface with a cylindrical aperture 23 which mates with a corresponding shaped surface formed on the under side of a swivel head 24. The swivel head 24 serves as a support for a transversely adjustable wheel head 25 which supports a rotatable grinding wheel 28. A clamping bolt 26 is provided for locking the wheel head 25 in adjusted position on the swivel head 24. It will be readily apparent from the foregoing disclosure that the swivel head 24 may be angularly adjusted relative to the wheel slide- 2i and the wheel head 25 may be adjusted trans- .versely relative to the'swivel head 24 to facilitate setting-up the machine.

Inorder to provide an angular feeding movement of the wheel slide 2|, the wheeL-slide base 22 is provided with. a. downwardly projecting cylindricalsurface' 21 which mates with a correspondingly shaped aperture formed in the upper surface of a base plate 28. The wheel slide base 22 may be clamped in adjusted angular position on the base plate 28 by means of clamping bolts (not shown) which ride in a circular T-slot formed in the upper surface of the base plate as (Fi .2).

The grinding wheel 28 is driven by an electric motor 38 which is mounted on the upper surface of the wheel head 25. A motor shaft 8| is connected by driving belts (not shown) with the grinding wheel spindle to rotate the grinding wheel 28. The driving belts are contain'ed within a belt guard 32 .(Fig. 1).

A suitable feedin mechanism is provided for feeding the wheel slide 2i transversely toward and from the work piece being ground. This mechanism may comprise a rotatable feed screw 85 which is rotatably supported by anti-friction bearings 38 and 31 carried by the wheel slide base 22. A half nut 38 depends from the under side of the wheel slide 2| and mates with the feed screw 85. In order to rotate the feed screw 88, a bevel gear 39 is keyed on the feed screw shaft (Fig. 2). The bevel gear 39 meshes with a bevel gear 48 which is mounted on the upper end of a vertically arranged rotatable shaft 41. In order to impart a feeding movement to the wheel slide 2| in any angular position of the wheel slide base 22, the shaft 4| is arranged with its axis coinciding with the axis of the cylindrical surface2l. A bevel gear 42 is mounted on the lower end of the shaft 4|. The bevel gear 42 meshes with a bevel gear 43 which is journalled in anti-friction bearings 44 and 45. The bearings 44 and 48 are fixedly mounted relative to the base In. A rotatable shaft 46 is slidably keyed to the bevel gear 43. A manually operable feed wheel 41 is mounted on the forward end of the shaft 46. It will be readily apparent from the foregoing disclosure that a manual rotation of the hand wheel 41 is transmitted to impart a transverse feeding movement to the wheel slide 2| and the grinding wheel 20.

A manually operable traverse mechanism is provided for imparting a longitudinal traversing movement to the table II. A hand traverse apron 58 is mounted on the front of the base In (Figs. 1, 12 and 13) A rotatable shaft 5| is journalled in anti-friction bearings 52 and 58 which are supported in the apron 58 (Figs. 12 and 13). The shaft 5| supports a bushing 54 which in turn supports a rotatable sleeve 55. A hand traverse wheel 58 is keyed on the forward end of the sleeve 55. A gear '51 is formed integral with the sleeve 56 and meshes with a gear 58. The gear 58 is supported by a bushing 59 which is rotatably mounted on a shaft 60. The shaft is supported by antifriction bearings 8| and 82 which are supported in the apron 58. A gear 68 is formed integral with the gear 58 and is meshed with a gear 84 which is keyed on the shaft 5|. A gear 65 fixedly mounted on the shaft ll meshes with a gear 68. The gear 66 is rotatably mounted on the shaft 80. A clutch member 6'! is slidably keyed on a bushing which is fixedly mounted on the shaft 68. A set of clutch teeth 68 on the clutch member 61 are arranged to engage a set of clutch teeth 08 formed integral with the gear 63 when the clutch member 61 is moved toward the front of the machine. A set of clutch teeth 10 are arranged to engage a set of clutch teeth ll formed integral with the gear 88 when the clutch member 81 is moved toward the rear of the machine.

A gear 12 is rotatably mounted on the shaft 80 and meshes with a rack bar 13 depending from the under side of the table II. A clutch member 14 is slidably keyed on a sleeve which is fixedly mounted on the shaft 68. The clutch member 14 is provided with clutch teeth I8 which are arranged to engage clutch teeth 16 formed integral with the gear 12 when the clutch member is moved toward the front of the machine. When clutch teeth 15 and 18 are engaged, a rotary motion of the shaft 88 is imparted to the gear 12 to traverse the rack bar 13 and work table I I longitudinally.

The clutch member 14 is arranged to be actuated by a bell crank lever 88 which is pivotally supported on a stud 8| (Figs. 12 and 13). The horizontal arm of the bell crank lever 88 is provided with a stud 82 which rides in a groove 88 formed in clutch member 14. A compression spring 84 surrounding a stud 85 engages the horizontal arm of the bell crank lever 88 and serves normally to maintain the clutch member I4 engaged. A slidably mounted rod 86 is arranged when moved toward the left (Figs. 12 and 13) to rock the bell crank lever 80 in a clockwise direction to disengage the clutch member 14 against the compression of the spring 84. The rod 88 is arranged to be actuated automatically in a manner to be hereinafter described by means of a slidable mounted rod 81 (Fig. 11) which is actuated by a frusto-conically shaped cam 88 (Fig. 8). The rods 86 and 81 are arranged in axial alignment with each other. An adjusting screw 89 and a lock nut 98 are mounted in the left hand end of the rod 81 to facilitate taking up lost motion between the rods 86 and 81.

The clutch 61 is actuated by means of a rock arm 93 which is pivotally supported by a stud 94. The arm 93 carries a stud 95 which rides in a groove 96 formed in the clutch member 61. The left hand end of the rock arm 93 is operatively connected to a slide rod 91 which projects from the front of the machine base I8. An actuating knob 98' is mounted on the outer end of the rod 91 to facilitate actuation of the clutch member 61.

The manually operable table traverse mechanism is preferably arranged so that either a rapid or a slow manual traversing movement of the table I I may be obtained by manipulation of the clutch member 61. In order to obtain a rapid manual traverse of the table II, the knob 98 is pulled out so as to slide the clutch member 61 forward to engage the clutch teeth 68 with the clutch teeth 69. In this position of the clutch 61, rotation of the hand wheel 56 will be transmitted through the sleeve 55, the gear 51, the gear 58, through the clutch member 61 to rotate the shaft 68. Rotation of the shaft 68 is transmitted through the clutch member 14 to rotate the gear 12 and through the rack bar 13 to traverse the table II longitudinally.

In order to obtain a slow manual traverse, the knob 98 is pushed in so as to slide the clutch member 61 rearwardly to engage the clutch teeth 18 with the clutch teeth 1 I. In this position of the clutch 61, rotation of the hand wheel 56 is transmitted through the sleeve 55, the gear 51, the gear 58, the gear 63, the gear 64, the shaft 5|, the gear 65, the gear 66 and the clutch member 61 to rotate the shaft 68 and thereby to transmit a slow manual traversing movement to the table I I. The ratio of the high and the low speed gear drive for the hand traverse mechanism is to 1.

Due to the gear ratio, rotation of the hand Wheel 56 to produce a 10 thousandths /100) of an inch adjustment of the table II when clutch member 61 is in low gear, will result in a 10 hundredths 0) of an inch adjustment if the clutch member 61 is shifted into high gear.

In order to facilitate a precise manual traversing movement of the table I I for a shoulder grinding operation and the like, a graduated dial 99 is provided. The dial 99 is rotatably supported on the sleeve 55 so that it may be readily adjusted relative to the hand traverse wheel 56 to facilitate setting the zero point of the scale in setting up the machine for a grinding operation requiring a manual traversing or positioning of the table II. A clamping screw 99a is provided for locking the dial 99 in adjusted position relative to the hand wheel 56.

The table II is reciprocated longitudinally by means of a hydraulically operated mechanism comprising a cylinder I88 (Fig. 14) which contains a slidably mounted piston I8I The cylinder I88 is fixedly mounted on the base I8. The piston MI is connected to a double end piston rod I82, the opposite. ends of which are connected to the table I I.

A suitable control valve mechanism is provided whereby the table II may be readily started and stopped when desired. A table actuated pilot and reversing valve mechanism are provided for controlling the admission to and exhaust of fluid from the table cylinder I88. A control apron I83 is mounted on the front of the machine base I8 (Figs. 1, 6, and 8). A control valve unit I84 is supported by a bracket I which surrounds the cylinder I88 (Figs. 6, 8, 10 and 11). The control valve unit I84 contains a reversing valve I86, a pilot valve I81, and a start-stop valve I88 (Figs. 6, 8, 9, l0 and 11). In the hydraulic diagram (Fig. 14), these valves have been diagrammatically separated to clarify the hydraulic connections and operation thereof.

The reversing valve I86 is a piston-type valve comprising a valve stem I89 having valve pistons 8, III and H2 formed integrally therewith. An actuating spool H3 is mounted on the end of the valve stem I89.

The pilot valve I81 is similarly a piston-type valve comprising a valve stem II5 having valve pistons H8, H1, H8, and H9 formed integrally therewith. An actuating spool I 28 is mounted on the end of the valve stem I I5. The pilot valve I81 is normally held in a central position by means of a balanced spring mechanism comprising a pair of flanged sleeves I2I and I22 which are slidably mounted on the opposite ends of the valve stem II5. Balanced compression springs I23 and I24 surround the sleeves I2I and I22 respectively and are interposed between flanges on sleeves I2I and I23 respectively and fixed collars on the valve stem H5. The springs I23 and I24 serve normally to maintain the pilot valve I81 in the position shown in Figs. 9 and 14.

The start-stop valve I88 is a piston-type valve comprising a valve stem I25 having valve pistons I21, I28 and I29 formed integrally therewith. A V-port I38 is formed in the valve piston I28 which is arranged when the valve I88 is in a start position to control the exhaust of fluid from the cylinder I88 and thereby to control the speed of movement of the table II. A serrated portion I3I on the valve stem I25 is engaged by a spring-pressed detent I32 supported by the casing of the valve I88. The serrated portion I3I and detent .I32 serve to maintain the valve stem I25 and V-port I38 in the desired rotary adjusted position during axial movement of the stem I25 when shifted to start and stop positions so as to facilitate starting and stopping the table II without disturbing the adjustment of the V-port I38.

A spool-shaped member I33 is connected by a stud I34 with a pivotally mounted Start-Stop lever I35. The lever I35 is supported by a stud I36 which is in turn fixedly mounted on the front of the apron I83. A knob I31 is mounted on the outer end of the valve stem I25 to facilitate a rotary adjustment of the V-port I38 so as to regulate the speed of the table I I.

A hydraulic system is provided for supplying fluid under pressure to the various mechanisms of the machine. This system comprises a motor driven fluid pump I48 which draws fluid through a pipe I4I from a reservoir I42. The pump I48 forces fluid under pressure through a pipe I 43 which conveys fluid under pressure to the table reciprocating and wheel feeding mechanisms. An adjustable pressure relief valve I44 is connected in the pipe I43 by means of which excess fluid under pressure may by-pass directly to the reservoir I42. By adjustment of the relief valve I44, the desired operating pressure may be maintained within the system.

Assuming the Start-Stop lever to be shifted in a counterclockwise direction to a start position, fluid under pressure in the pipe I43 enters a 7 valve chamber located between the valve pistons III and I I2 01 the reversing valve I and passes out through a pipe I00 into a cylinder chamber I00 at the right hand end of the cylinder I00. Fluid under pressure entering cylinder chamber I00 causes the piston IOI and table II to move toward the left. During this movement of the table II, fluid within a cylinder chamber I01 exhausts through a pipe I00 into a valve chamber located between the valve pistons H0 and III and passes out through a pipe I00, through the V-port I00 in the Start-Stop valve I00 and through an exhaust pipe -IOI into the reservoir I02. The speed of movement of the piston IM and the table II may be adjusted by a rotary adjustment of the knob I01 and the V-port I00.

The pilot valve I01 is arranged to control the admission to and exhaust of fluid from end chambers I00 and I02 formed in opposite ends of the reversing valve I00. Fluid under pressure in the pipe I00 is admitted at all times to a valve cham ber I00 located between the valve pistons H1 and I ll of the pilot valve I01.

When the pilot valve stem I I0 is shifted toward the right (Fig. 14), a port is uncovered to pass fluid under pressure from the valve chamber I55 through a passage I00, through a throttle valve I01 into the end chamber I00 of the reversing valve to shift the valve stem I00 toward the left at a slow rate until a relatively large port I00 is uncovered by valve piston II2 to allow fluid under pressure to by-pass the throttle valve I01 and to pass in a relatively large volume into the end chamber I00 to snap the reversing valve rapidly into a reverse position. This movement of the reversing valve I00 serves to pass fluid under pressure through the pipe I00 into cylinder chamber I 01 to start movement of the piston "I and table I I toward the right.

During the shifting of reverse valve stem I 00 toward the left, fluid within the end chamber I02 is free to exhaust through a pipe I00 into a valve chamber I00 and out through an exhau pipe I01 into the reservoir I02.

When the pilot valve stem H0 is shifted toward the left (Fig. 14), a port is uncovered to pass fluid under pressure from the valve chamber I00 through a passage I00, through a throttle valve IOI into the end chamber I02 to shift the valve stem I 00 toward the right at a slow rate until a relatively large port I00 is uncovered by valve piston I I0 to allow fluid under pressure to by-pass the throttle valve IOI and to pass in a relatively large volume into the end chamber I02 to snap the reversing valve rapidly into a reverse position. This movement serves to position the reversing valve I00 in the position illustrated in Fig. 14.

A manually operable reversing lever I is mounted on the front end of a rock shaft III which is rotatably mounted in the apron I00. A sleeve I12 is keyed on the inner end of the rock shaft I1I. The sleeve I12'is provided with an integral upwardly extending arm I10 which is connected by a stud I10 with the spool III, on reverse valve stem I00. The sleeve I12 is also connected in a mannento be hereinafter described to the spool I on -t'l1e--pilo.t. valve I I plate I10. A compression spring I11 serves normally to maintain the lever I10 in an uppermost position in the path of a pair of Unstable table dogs I10 and I10 (Figs. 1 and '1). The dogs I10 and I10 are adjustably supported by bolts which slide in a T-slot formed in the front edge of the table II. The plate I10 is formed Integral with a rock shaft I00 which is supported in a bearing "I in the apron I00. A downwardly extending rock arm I02 is keyed to the inner 'end of the rock shaft I00. The rock arm I02 is provided at its lower endwith a stud I00 which rides in the spool I20 on the pilot valve stem III.

A rock arm I00 (Figs. 6 and 7) is rotatably supported on the rock shaft I00. A gear segment I00 is formed on the lower end of the arm I00 which meshes with an idler gear I00. The gear I00 is rotatably supported on a stud I01. The gear I00 meshes with a gear I00 which is formed integral with the sleeve I12.

A lost motion connection is provided between the rock arm I02 and the rock arm I00. The rock arm I02 is provided with oppositely extending lugs I00 and IOI which are provided with adjusting screws I02 and 100 respectively. The adjusting screws I02 and I00 are arranged in the path of a pair of rearwardl extending lugs I00 and I00 formed integral with the rock arm I00. The lost motion connection is provided so that after the reverse valve I00 has been shifted into a reverse position, the released compression of the spring I20 or I20 may return the pilot valve I01 to a central position as shown in Fig. 14.

It will be readily apparent from the foregoing disclosure that either the table dog I10 or the dog I10 engages the reversing lever I10 to initiate a reversal of the table, the initial movement of the reverse lever I-10 serves simultaneously to shift both reversing valve I 00 and pilot valve I01 by movement of the table II. This movement of the valves continues until the valve piston I I I cuts of! exhaust of fluid from the cylinder I00 to stop the movement of the table II. When the reverse valve I00 is in this position, the pilot valve stem III has moved a suilicient distance so that fluid under pressure in the valve chamber I00 may pass through either passage I00 or I00 to cause a slow shifting movement of the reversing valve until the port I00 or I00 is opened to snap the reversing valve rapidly and positively into a reverse position by means of fluid under pressure.

The relatively slow movement of the reversins valve I00 as governed by throttle valves I01 and IOI serves to provide a tarry or dwell at the ends of the table stroke during the period of reversal. By adjustment of the throttle valves I01 and NI, the period of dwell at either or both ends of the table stroke may be adjusted as desired. To facilitate adjustment of throttle valves I01-and IOI, adjusting knobs I00 and I00 are provided on the front of the machine (Figs. 1, 8 and 10).

a A hydrau1ically operated feeding mechanism is provided for automatically producing an infeeding movement of the grinding wheel 20 during the dwell period at the ends of the reciprocatory stroke .of the table II. This mechanism prefstem III. A manual actuation of the lever 'I10""" -1rah1z gomprises a single vane-type fluid motor serves to shift reversing valve I00 and pilot valve I01 manually to-.r,everse the direction of movement of piston I 0| and table I I It is desirable to provide a suitable table actuated mechanism for-automatically actuating the reversing valve I00 and the pilot valve I01.

200 havfiiia rotorshaft 2" which supports a rotor 202 (Figs. 3, 4 and 14). A single vane 200 is fixedly mounted on the rotor 202 which is arranged to rotate less than 360' within a motor chamber 200. An arcuate shaped block 200 having end stop surfaces 200 and :01 serves to limit Areversing lever I10 isverticaliy slidableona 1s theoscillatingstrokeoithevansm. Thsrotor shaft 20I projects from the front of the machine base and is provided on its outer end with a plate 260 having a radially extending T-slot (Figs. 1 and 3) which supports an adjustable stud 203. The stud 209 may be adjusted relative to the plate 208 so that it is either concentric with or eccentric relative to the axis of the rotor shaft 20I.

In order to transmit a feeding movement to the feed screw 35, a yoke 2l0 straddles the stud 209. The yoke 2I0 is'formed integral with a rock arm 2 which is arranged to oscillate about the axis of the shaft 4-6. An arm 2I2 is formed integral with the arm 2I I so as to form a bell-crank lever. The arm 2I2 carries a stud 2I3 which serves as a support for a pawl arm 2. The pawl arm 2 is provided with a stud 2I5 which supports a small gear 2I6. The gear 2I6 serves as .a feed pawl and meshes with a gear 2 I I mounted on the feed shaft 46. A ball clutch (not shown) is interposed between the small gear 2 I6 and its supporting stud 2I5. The ball clutch is arranged so that the gear 2I6 rolls idly over the teeth of the gear 2 I 1 during an upward movement of the pawl arm 2| 4. During downward movement of the pawl arm 2I4, the ball clutch locks the gear 2I6 to the pawl arm 2I4 and thereby imparts a rotary motion to the gear 2II. During each oscillation of the motor vane 203, the eccentric stud 209 imparts a down and an up stroke to the pawl arm 2I4 and gear 2I6 so as to impart an infeeding movement to the grinding wheel 20 at each end of the reciprocatory stroke of the table II. This feeding movement continues until the upper end of the pawl arm M4 is engaged by a stop abutment 2 I8 carried by the feed wheel 41 which stops the infeeding movement Of the grinding wheel 20 when the Work piece being ground has reached a predetermined size. It will be readily apparent from the foregoing disclosure that the extent of each feeding movement may be adjusted by varying the eccentricity of the stud 209.

A reversing valve 220 (Figs. 4, 14 and 15) is provided for controlling the admission to and exhaust of fluid from the Wheel feed motor 200. The valve 220 is a piston type valve comprising a valve stem 22I having valve pistons 222, 223 and 224 formed integrally therewith. The fluid pressure pipe I43 is connected to a control valve 225 which is actuated by a knob 226 to control the admission of fluid under pressure through a passage 221 to ports 228 and 229 in the reversing valve 220 to control the starting-stopping and speed of movement of the motor vane 203. In the position of Valve 220 (Figs. 4, 14, and 15), fluid under pressure enters through the port 229 into a valve chamber formed between the valve istons 223 and 224 and passes through a passage 23I into a motor chamber 232 to cause the motor vane 203 to revolve in a clockwise direction. During this movement of the motor vane 203, fluid within motor chamber 233 is forced out through a passage 234 into a valve chamber formed between the valve pistons 222 and 223. Fluid exhausting into the latter chamber passes out through an exhaust port 236 and an exhaust pipe 231 to the reservoir I42.

The motor vane 203 continues its clockwise or counterclockwise movement until it engages a stop face 206 or a stop face 201 on the block. The pressure remains on the operative side to hold the vane 259 against the stop face until the control valve 220 is again shifted thereby preventing movement of the feed pawl 2 I 4.

It is desirable that the valve 220 be actuated in timed relation with the table reciprocation so that the infeed of the grinding wheel may be obtained at the end of the table stroke during the period of reversal. In the preferred construction, the control valve 220 is actuated in timed relation with the actuation of the table reversing valve I06. The valve stem 22I is connected by a stud 238 with a link 239, The other end of the link 239 is connected by a stud 240 with the arm I13 which actuates the reversing valve I06 (Figs. 4, 6 and 14). It will be readil apparent from the foregoing disclosure that the valve 220 will be actuated by and in timed relation with the table reversing valve I06.

- It is also desirable that the infeeding movement of the grinding wheel 20 be completed during table reversal before the table I I starts moving in the oppositedirection. This is preferably accomplished by constructing the valve 220 so that the timing of the valve is reset ahead of dead center for the .reverse stroke. As illustrated in Figs. 4, 14, 15 and 16, a sliding valve sleeve 24I surrounds the valve pistons 222, 223 and '224. The sleeve 24I is slightly longer than the surrounding motor casing and is arranged to be moved in an axial direction either by means of a shoulder on the valve stem 22I at one end or a collar 243 at the other end. The sleeve 24I is provided with a plurality of ports 228a, 229a, 230a, 235a, and 236a which correspond with the spacing of the ports 228, 229, 230, 235 and 236 in the casing. The ports 228a, 229a, 230a, 235a, and 236a in the sleeve 24I are enlarged adjacent to the periphery of the sleeve 24I so that in any position of the sleeve 24I, they are in full communication with the ports 228, 229, 230, 235 and 236. The sleeve 24I is arranged so that it has an axial stroke of approximately /3 of an inch relative to the case. A friction plunger 242 mounted in the casing frictionally engages a plane surface 244 formed on the sleeve 24I to maintain the sleeve against movement except when moved by the stem 22I. Q

When the valve stem 22I is moved toward the left (Fig. 15) by actuation of the reversing valve I06 (Fig, 14), the valve pistons 222, 223 and 224 slide Within the sleeve 24! until the collar 243 engages the end of the sleeve 24! and continued movement of the valve stem 22I then slides the sleeve 24I toward the left to reset the ports 228a, 229a, 230a, 235a and 236a. The resetting of the sleeve 24I serves to advance the position of the ports 228a, 229a, 230a, 235a and 236a and thereby to advance the picker feed function so that it completes an infeeding movement of the grinding wheel during the dwell provided at table reversal before the table II starts moving in the reverse direction. The sleeve 24I functions in a similar manner when the valve stem 22I is shifted toward the right.

To eliminate air from the hydraulic system, it is desirable to provide suitable means for automatically bleeding the system during operation of the machine. A pair of bleeder pipes 250 and 25I are connected to opposite ends of the table cylinder I00 (Fig. 14). The bleeder pipes 250 and 25I are connected to the feed control valve 220 so that the pressure side of the cylinder is automatically vented. The sleeve 24I is provided on its outer periphery with a pair of slabbed portions which form a pair of valve chambers 253 and 255. In the position shown in Figs. 14 and 15, fluid bleeding through pipe 250 passes through a port 252 and through the valve chamber 253 and drains into the reservoir I 42. When reversing valve I06 and valve 220 are in reverse posichamber tions 50 that fluid under pressure is supplied to cylinder chamber I 41, fluid bleeds from cylinder Ill, through the bleeder pipe 25I, through a port 254 and the valve chamber 255 into the reservoir I42. 'It will be readily apparent from the foregoing disclosure that the pressure side of the table cylinder I is continuously vented to bleed any air which may leak into the system into the reservoir.

The operation of the improved grinding machine will be readily apparent from the foregoing disclosure. Assuming all adjustments to have previously been made, the workdrive motor I8, the wheel drive motor 30 and the fluid pump motor are started. A work piece to be ground is mounted on headstock center I and footstock center I! with the work piece being driven in the conventional manner, namely, by means of a work driving dog, The Start-Stop lever I35 is moved in a counterclockwise direction (Figs. 8 and 14) to open the V-port I30 which allows fluid to exhaust from the cylinder chamber I41 thereby starting reciprocation of the table II. The table dogs I18 and I19 actuating the reverse lever I serve to reverse the table movement in a manner above described at the ends of the predetermined stroke. Through actuation of the feed control valve 220, the grinding wheel 20 is automatically fed into the work piece being ground during the dwell at reversal at each end of the table stroke. The infeeding movement of the grinding wheel continues intermittently at the ends of the table stroke until the stop abutment IIS on the feed wheel 41 engages the end of the pawl arm 2 I I.

When it is desired to stop the operation of the machine, the lever I35 is moved in a clockwise direction into the position illustrated in Fig. 14, to close the V-port I 30 thereby cutting ofl! the exhaust of fluid from the cylinder I00 to stop the reciprocation of the table II. When the valve I00 is moved to a stopped position, the cam 00 recedes so that the released compression of the spring 84 engages the clutch member 14 to render the manually operable traverse wheel 50 operative. In this position of the valve I08 fluid may by-pass directly between cylinder chambers I 40 and I" to facilitate manual traverse of the table II. Fluid also by-passes directly from the pressure pipe I43 into the reservoir I42 thus preventing wire-drawing of the pressure fluid and resultant excessive heating of the fluid.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a grinding machine having a longitudinally reciprocable table, a piston and cylinder to reciprocate said table, a reversing valve therefor, an end chamber in each end of said valve, 8. pilot valve, a stop and start valve to control the exhaust of fluid from said cylinder to start and stop table reciprocation, table-actuated lever which is operatively connected to shift both the pilot and reversing valves to stop the table, fluid connections between each of the end chembers and the pilot valve positively to shift the 12 reversing valve slowly, a throttle valve in each of said connections to regulate said slow movement of the reversing valve in either direction to provide a predetermined table dwell at reversal, and separate ports in the reversing valve which are opened after a predetermined slow movement to by-pass fluid around the throttle valves into the end chambers rapidly to shift the reversing valve into its reverse position.

2. In a grindin machine having a longitudinally reciprocable table, a piston and cylinder to reciprocate said table, a reversing valve therefor, an end chamber in each end of said valve, a pilot valve, a stop and start valve to control the exhaust of fluid from said cylinder, a table actuated lever which is operatively connected to shift both the pilot and reversing valves to stop the table, fluid connections between each of the end chambers and the pilot valve positively to shift the reversing valve slowly, a throttle valve in each of said connections to regulate said slow movement of the reversing valve in either direction, separate ports in the reversing valve which are opened after a predetermined slow movement to by-pass fluid around the throttle valves into the end chambers rapidly to shift the reversing valve into its reverse position, and separate passages between the end chambers and the pilot valve which are arranged to facilitate unrestricted exhaust of fluid from the inactive end chamber.

3. In a grinding machine having a reciprocable work table, a piston and cylinder to reciprocate said table, a reversing valve therefor, end chambers in opposite ends of said valve to facilitate fluid pressure actuation of the valve, a pilot valve for controlling the shifting of the reversing valve, a start and stop valve to control exhaust of fluid from said cylinder, a table-actuated lever mechanism to shift both the pilot and reversing valves so as to cut off exhaust of fluid from said cylinder thereby to stop the table, connections between said pilot and reversing valves thereafter being arranged to admit fluid to one of said end chambers first at a slow rate and then rapidly to shift the reversing valve into a reverse position, balanced springs normally to maintain said pilot valve in a central position, and passages between the end chambers and pilot valve which are interconnected when the pilot valve is in a central position to facilitate manual actuation of the reversing valve.

4. In a grinding machine having a reci rocable table, a piston and cylinder to reciprocate said table, a reversing valve therefor, end chambers in the opposite ends of said valve, a pilot valve for controlling the shifting of the reversing valve. 9. start and stop valve to control the exhaust of fluid from said cylinder, 9. table-actuated lever mechanism to shift both the pilot and reversing valves so as to cut oil exhaust of fluid from said cylinder thereby to stop the table, fluid connections between said pilot and reversing valves thereafter being arranged to admit fluid to one of said chambers flrst at a slow rate and then rapidly to shift the reversing valve into a reverse position, means normal y to maintain the the pilot valve in a central position, and passages between the end chambers and pilot valve which are interconnected when the pilot valve is in a central position, said latter passages being arranged to facilitate exhaust of fluid from the inactive end chamber when the pilot valve is shifted from a central position.

Q. In a grinding machine having a reciprocable table, a piston and cylinder to reciprocate said table, a reversing valve therefor, end chambers in opposite ends of said valve, a pilot valve, a stop and start valve to control the exhaust of fluid fromsaid cylinder, a lever mechanism to shift both the pilot and reversing valves so as to cut-off exhaust of fluid from said cylinder thereby to stop the table, fluid connections between said pilot and reversing valves thereafter being arranged to admit fluid to one of said end chambers first at a slow rate and then rapidly to shift the reversing valve into a reverse position, means normally to maintain the pilot valve in a central position, passages between the end chambers and pilot valve which are interconnected when the pilot valve is in a central position, and lost motion connections in said lever mechanism to facilitate movement of the pilot valve to a central position after a .table reversal has been completed.

6. In a grinding machine having a reciprocable table, a piston and cylinder to reciprocate said table, a reversing valve therefor, a manually operable lever to shift said valve, end chambers in each end of said valve, a pilot valve to control the admission to an exhaust of fluid from said end chambers, a reversing lever to actuate said pilot and reversing valves to stop said table, adjustable dogs on said table to actuate said lever, independent passages between the pilot valve and each of'said end chambers, independent throttle valves in each of said passages to facilitate a slow initial shifting of the reversing valve when the table has been stopped, and independent ports in the reversing valve to by-pass fluid around the throttle valves after a predetermined slow shifting movement of the reversing valve rapidly and positively to complete the movement of the reversing valve, said passages being arranged when the pilot valve is in a central position to interconnect said end chambers to facilitate manual actuation of the reversing valve.

7. In a grinding machine having a reciprocable work table, a piston and cylinder to reciprocate said table, a reversing valve therefor, a pilot valve for controlling the shifting of said reversing valve, a start and stop valve to control the exhaust of fluid from said cylinder to facilitate starting and stopping table reciprocation, a manually operable table traverse mechanism including a normally engaged clutch, a cam on said start and stop valve, and a slidably mounted plunger actuated by said cam to disengage said clutch when the start and stop valve is shifted to a start position to render the manually operable traverse mechanism inoperative during hydraulic reciprocation of the table.

8. In a grinding machine having a reciprocable table, a piston and cylinder to reciprocate said table, a reversing valve therefor, a pilot valve for controlling the shifting of said reversing valve, a start and stop valve to control the exhaust of fluid from said cylinder to facilitate starting and stopping table reciprocation, a manually operable table traverse mechanism including a clutch, a spring normally to maintain said clutch in an engaged position, and a cam on said valve to facilitate releasing said spring so as to engage the clutch and thereby to render the manu- I ally operable traverse mechanism operative when the start and stop valve is moved to a stop position.

9. In a grinding machine having a longitudinally reciprocable table, a piston and cylinder to 14- reciprocate said table, a reversing valve therefor, a transversely movable wheel slide, a rotatable grinding wheel thereon, a wheel feeding mechanism including a fluid motor, a control valve therefor, operative connections between said valve and the table reversing valve whereby said control valve is actuated in timed relation with the table reversing valve to impart a feeding movement to the grinding wheel during table reversal, and a slidably mounted sleeve in said control valve which is moved longitudinally during shifting of the control valve to reset the timing of said valve ahead of dead center so that the infeeding movement of the grinding wheel is completed before the table start movement in the reverse direction.

10. In a grinding machine having a longitudinally reciprocable table, a piston and cylinder to reciprocate said table, a reversing valve therefor, a transversely movable wheel slide, a rotatable grinding wheel thereon, a reversing valve for the feed motor including a slidably mounted valve stem having a plurality of integrally formed pistons, a slidably mounted sleeve surrounding said stem and pistons, a friction plunger normally to hold said sleeve against longitudinal movement,

a plurality of ports in said sleeve to admit fluid to and exhaust fluid from the motor chambers, and projections on said valve stem which are arranged to engage and shift said sleeve longitudinally during reversal of said control valve to facilitate advancin actuation of the infeeding movement so that the infeed is completed during dwell at table reversal before the table starts movement in the reverse direction.

11. In a grinding machine having a reciprocable table, a piston and cylinder to reciprocate said table, a reversing valve therefor, a pilot valve for controlling the shifting of the reversing valve, a rotatable grinding wheel, a transversely movable slide therefor, a feedin mechanism for said slide including a fluid motor, a reversing valve therefor, operative connections between the table reversing valve and the motor reversing valve whereby the latter valve is actuated by and in timed relation with the table reversing valve to impart an infeeding movement of the grinding wheel during table reversal, bleeder pipes connectin opposite ends of table cylinder with the motor reversing valve, and separate ports in said valve which are arranged so that the pressure end of the table cylinder is automatically and continuously bled.

12. In a grinding machine having a reciprocable table, a piston and cylinder to reciprocate said table, a reversing valve therefor, a pilot valve for controlling the shifting of the reversing valve, a rotatable grindin wheel, a transversely movable slide therefor, a feeding mechanism for said slide including a fluid motor, a reversing valve therefor, operative connections between the table reversing valve and the motor reversing valve whereby the latter valve is actuated by and in timed relation with the table reversing valve to impart an infeeding movement of the grinding wheel durin table reversal, bleeder pipes connecting opposite ends of the table cylinder with v the vane motor reversing valve, separate ports in said valve, and chambers in said valve which are opened to the atmosphere so that the pressure end of'the table cylinder is automatically and continuously bled.

13. In a grinding machine having a transversely movable rotatable grinding wheel, a reciprocable table, a piston and cylinder to reciprocate assess?- 15 said table. a reversing valve therefor, a pilot valve for controlling the shifting of the reversing valve, a bleeder control valve for controlling bleeding fluid irom opposite ends of said cylinder, bleeder pipes connecting opposite ends of the table cylinder with said valve. separate ports in said bleeder control valve and operative connections between the table reversing valve and the bleeder control valve whereby the latter valve is actuated by and in timed relation with the reversing valve to render one or the other of said ports operative so that the pressure end of the table cylinder is automatically and continuously bled through one of said ports. 4

WALLACE H. WOOD.

18 REFERENCES mm The following references are of record in the tile 0! this patent:

UNITED STATES PATENTS Number Name Date 1,943,061 Douglas Jan. 9, 1934 2,000,805 West et a1. May 7, 1935 2,091,425 Wood Aug. 31, 1937 2,101,787 Amidon ..'Dec. 7, 1937 2,127,877 Maglott Aug. 23, 1938 2,294,872 Wood Sept. 1, 1942 2,376,236 Decker et a1. May 15, 1945 

